"Throughout the human life span there remains a constant two-way interaction between psychological states and the neurochemistry of the frontal lobes, a fact that many doctors do not pay enough attention to. One result is the overreliance on medications in the treatment of mental disorders. Modern psychiatry is doing too much listening to Prozac and not enough listening to human beings; people’s life histories should be given at least as much importance as the chemistry of their brains. The dominant tendency is to explain mental conditions by deficiencies of the brain’s chemical messengers, the neurotransmitters.

As Daniel J. Siegel has sharply remarked, “We hear it said everywhere these days that the experience of human beings comes from their chemicals.” Depression, according to the simple biochemical model, is due to a lack of serotonin — and, it is said, so is excessive aggression. The answer is Prozac, which increases serotonin levels in the brain. Attention deficit is thought to be due in part to an undersupply of dopamine, one of the brain’s most important neurotransmitters, crucial to attention and to experiencing reward states. The answer is Ritalin. Just as Prozac elevates serotonin levels, Ritalin or other psychostimulants are thought to increase the availability of dopamine in the brain’s
prefrontal areas.

This is believed to increase motivation and attention by improving the functioning of areas in the prefrontal cortex. Although they carry some truth, such biochemical explanations of complex mental states are dangerous oversimplifications — as the neurologist Antonio Damasio cautions: "When it comes to explaining behavior and mind, it is not enough to mention neurochemistry... The problem is that it is not the absence or low amount of serotonin per se that “causes” certain manifestations.

Serotonin is part of an exceedingly complicated mechanism which operates at the level of molecules, synapses, local circuits, and systems, and in which sociocultur